Kerr-lens mode-locked 2.3-μm Tm:YLF laser as a source of femtosecond pulses in the mid-infrared.

We report what is to our knowledge a new source of femtosecond pulses in the mid-infrared, based on a Kerr-lens mode-locked (KLM) Tm:YLF laser at 2303 nm. An undoped ZnSe substrate was included in the resonator to provide enhanced nonlinear phase modulation during KLM operation. The Tm:YLF laser was end-pumped with a continuous-wave Ti : sapphire laser at 780 nm.

2.3-μm Tm:YLF laser passively Q-switched with a Cr:ZnSe saturable absorber.

We report, what is to our knowledge, the first passively Q-switched operation of a 2.3-μm Tm:YLF laser by using a Cr:ZnSe saturable absorber. In the experiments, a tunable Ti:sapphire laser was used to end pump the Tm:YLF gain medium inside an x cavity.